The latest controversy revolves around Siri, which received positive reviews when it was released as a core element on the iPhone 4S late last year. Using both voice recognition and artificial intelligence technologies, Siri is designed to respond to voice inquiries such as "what's the weather today" or "find me a well-rated Greek restaurant in Hoboken" and pull together the needed information to deliver the result to the user.

The problem, according to a class-action lawsuit filed by New York resident Frank Fazio: The iPhone 4S's Siri feature does not perform as advertised. Fazio purchased the iPhone 4S solely for the Siri functionality he saw in Apple commercials, which showed users getting impressive assistance with such tasks as making appointments, finding restaurants, learning to play guitar, and tying ties.

Immediately after purchasing the iPhone 4S, Fazio "realized that Siri was not performing as advertised. For instance, when he asked Siri for directions to a certain place or to locate a store, Siri either did not understand what Fazio was asking or, after a very long wait time, responded with the wrong answer," according to the lawsuit.

Fazio's problems with Siri are evidently not isolated. Some observers have said that Siri actually worked beautifully once upon a time -- but has steadily worsened in recent months. "I used to ask Siri, 'What are the five biggest lakes in California?' and it would come back with the answer," Apple co-founder Steve Wozniak told The Daily Beast in January. "Now it just misses. It gives me real estate listings."

What's more, Wozniak complained that Siri could not reliably connect to the back-end servers that power the system: "With the iPhone 4 I could press a button and call my wife. Now on the 4S I can only do that when Siri can connect over the Internet. But many times it can't connect. I've never had Android come back and say, 'I can't connect over the Internet,'" he said.

Cult of Mac, too, has criticized Siri, going so far as to say outright that it's so "broken," it did not make it on to the new iPad. "Siri -- a beta by Apple's own admission -- is quantifiably dumber, less intelligent, and less useful than it was just five months ago when it first launched," the blog posted.